Anti-nutritional Factors In Soybean Research Articles

Lactobacillus acidophilus and Lactobacillus cereus-containing products do reduce soybean antinutritional factors

Abstract. Soybean has shown over the years to be a reliable plant protein source to excellently substitute the high cost fishmeal in aquaculture diets. However, antinutritional factors (ANFs) limit its usage in aquaculture feeds. Therefore, the current study was designed to test the efficacy of three substrates containing different microorganisms that are capable of reducing soybean ANFs in a 3-month period at a low pH of 2.8. Full fat soybean (USB) was fermented using Anaerobic waste extract from Recirculating Aquaculture System sludge trap (RASW); Biocentric® Feed probiotic powder (BIOP); Oakland® double cream yoghurt (3x 106 CFU ml¯¹) (OY), Control treatment which had no substrate that contained fermenting microorganism (SRR). Each treatment was conducted in three replicates at 2.8 pH. The untreated soybean granules recorded a numerical protein content of 48.56%. The BIOP fermented soybean recorded significantly higher protein content as compared to the other soybean meal fermented with the other substrates. There was also a significant decrease in the soybean content of the amino acid lysine upon fermentation with the four treatments. Fermentation of the soybean with the four treatments was not significantly different in relation with their soybean lipid content, crude fibre content, methionine + cysteine, dry matter content, urease activity and gross energy content (P > 0.05). There was an overall significant decrease in the ANFs when soybean was fermented with the four treatments, with four out of six analysed ANFs parameters content showing a significant decrease upon fermentation (P < 0.05). Fermentation of the soybean with RASW resulted in a significant decrease of trypsin inhibitor content as compared to the rest of the treatments. The USB recorded a numerical value of 43.80 for trypsin inhibitor, whereas RASW fermented soybean recorded least trypsin inhibitor of 3815 ± 010 mg/g. In conclusion, the current study showed that the fermentation substrates used are capable of reducing soybean ANFs, with a slight decrease in soybean protein content.

PSV-22 Nutrient Digestibility of Deactivated Soybean and Soybean Extruded at Different Temperatures by Weanling Pigs

Abstract The apparent and standardized ileal digestibility (AID and SID) of AA and CP and the apparent total tract digestibility (ATTD) of DM, GE, CP, NDF, and ADF of deactivated soybean (DS) and raw soybean (RS) extruded at 82°C (RS82), 122°C (RS122) and 137°C (RS137) were evaluated. RS was extruded mixed with corn starch (396.5g/kg RS and 603.5g/kg corn starch) in a single-screw extruder (MEX 250, Manzoni, Campinas, Brazil). Thirty-six barrows (7.26±0.94 kg BW) were fed a nitrogen free (N-free) diet, or four diets composed of 30% of each ingredient, as the only source of N, substituting for starch in N-free diet. Pigs were fed at 2.8 x maintenance (2.8 x 106 kcal digestible energy/kg BW0.75) for 10 days (5 d adaptation and 5 d feces collection), and on day 11 piglets were euthanized for ileal digesta collection. A randomized block design was used, with 8 replicates, using the pig as the experimental unit. ANOVA was performed and means were separated using Tukey test (5%). Increasing extrusion temperatures reduced trypsin inhibitors concentrations, from 29.47 in RS to 4.92, 2.24, and 1.48 mg/g CP in RS82, RS122, and RS137, respectively, and 1.39 mg/g CP was verified in DS. The AID and SID of CP and AA, as the ATTD of CP of RS122, RS137 and DS were similar (P >0.05), but 10–62% greater (P< 0.05) than of RS82. The ATTD of GE in RS122 was 3–4% higher (P< 0.05) compared to DS and RS82. RS82 and RS122 showed ATTD of EE 12–16% higher (P< 0.05) than DS. The ATTD of GE and EE of RS137 were similar (P >0.05) to the others ingredients. No effects (P >0.05) on ATTD of NDF and ADF were observed. Extruding soybean at 122oC improved CP, AA, and GE digestibility in young pigs, whereas extrusion at 82oC did not inactivated soybean antinutritional factors.

PSIX-15 Extrusion of corn-soybean product blends in replacement of soybean meal in weanling pig diets

Abstract Extrusion is a thermomechanical process that can reduce the content antinutritional factors in soybean, improving the use of its nutrients by pigs. The purpose of this study was to evaluate extruded corn-soybean grain blends, replacing soybean meal in weanling pig diets, on pig growth performance from 21 to 63 d old. Ground corn and the corn-soybean blend (75.27% of ground corn and 24.73%) were extruded at 120°C in a single-screw extruder. One hundred and sixty crossbred weaned pigs (6.02 ± 0.63 kg) were used in a three-phase feeding program (21-35, 36-49, 50-63 days of age) and fed a basal diet (BD - extruded corn, dairy product, spray dried plasma, and soybean meal) or one of four diets in which soybean meal was replaced for deactivated (DS) or extruded (EX) corn-soybean blend, in 50 or 100%, generating diets DS50, DS100, EX50 and EX100. Diets were formulated to provide 3.40, 3.38, and 3.20 Mcal of ME/kg; 220, 215, and 190 g/kg of CP; and 14.5, 13.3, and 10.9 g/kg of digestible lysine, in phases 1, 2, and 3, respectively. A randomized block design based on initial BW was used. The data was submitted to ANOVA and means were separated using Tukey test (5%). Pigs fed diets EX50 and EX100 presented reductions (P< 0.05) in ADG (16-50%), final BW and G:F (13-33%) compared to pigs submitted to diets SBM100, DS50 or DS100 in phases 1 and 2. ADG, ADFI, and G:F of pigs were not affected (P >0.05) in phase 3, but final BW of pigs fed extruded corn-soybean blend were lower (P< 0.05) than that of pigs fed other diets. The extrusion temperature may have been insufficient to inactivate the anti-nutritional factors of soybean that probably reduced pig growth performance. The inclusion of extruded corn-soybean blend in replacement of soybean meal reduced growth performance of pigs.

PSI-12 Effect of a carbohydrase mixture on apparent and standardized ileal digestibility of amino acids in dry extruded-expelled soybean meal fed to growing pigs

Abstract Heat treatment could effectively decrease the antinutritional factors in soybean during meal processing. One such progress is the combination of extrusion with expelling, which produces the dry extruded-expelled soybean meal (DESBM), and there is a great interest in exploring its utilization as a dietary ingredient for swine. Thus, eight ileal-cannulated barrows (initial BW = 30 ± 1.3 kg) were used to determine the ileal amino acid (AA) digestibility of DESBM fed to growing pigs with or without multi-carbohydrase (MC) supplementation. Pigs were randomly assigned to 1 of 4 treatments in a replicated 4 × 4 Latin square design to give eight observations per treatment. The experimental diets were formulated to contain one of the two batches of DESBM (DESBM-1 and DESBM-2) as the sole source of protein. All diets contained titanium dioxide (0.3%) as an indigestible marker to calculate nutrient digestibility. Each experimental period lasted for seven days, and ileal digesta samples were collected on d 6 and d 7. The standardized ileal digestibility (SID) of AA were calculated using published mean values to estimate ileal endogenous AA losses. Data were analyzed using the mixed model procedures of SAS, and the final model had treatment, batch, and the interaction between treatment and batch as the main effects. In general, the SID of AA in DESBM-1 and DESBM-2 were not different, such as Ile, Lys, Met, Thr, and Val, which averaged 88.97%, 89.77%, 89.08%, 84.38%, and 86.85% respectively. There were no effects of MC supplementation on AID and SID of AA digestibility in DESBM except for the AID of Trp (P < 0.05). Also, there were no interaction effects of MC supplementation and batch on AA digestibility in DESBM. In conclusion, enzyme supplementation did not improve the AID and SID of AA in DESBM fed to growing pigs.

The development of new soybean strain with ti and cgy1 recessive allele

Soybean [Glycine max (L.) Merr.] seed is an important dietary source of protein, oil, carbohydrate, isoflavone and other various nutrients for humans and animals. However, there are anti-nutritional factors in the raw mature soybeans. Kunitz trypsin inhibitor (KTI) protein and stachyose are the main anti-nutritional factors in soybean seed. The α′-subunit of β-conglycinin protein exhibit poor nutritional and food processing properties. The genetic removal of the KTI and α′-subunit proteins will improve the nutritional value of the soybean seed. The objective of this research was to develop a new soybean strain with KTI and α′-subunit protein free (titicgy1cgy1 genotype) and proper agronomic traits. A breeding population was developed from the cross of the Bl-1 and 15G1 parents. A total of 168 F2 seeds from the cross of the BL-1 and 15G1 parents were obtained. The segregation ratios of 9: 3: 3: 1 (104 Ti_Cgy1_: 30 Ti_cgy1cgy1: 21 cgy1cgy1Ti_: 13 titicgy1cgy1) between the Ti and Cgy1 genes in the F2 seeds were observed (χ 2= 5.12, P=0.5-0.10). Two F4 plant strains with proper agronomical traits and titicgy1cgy1 genotype (free of both KTI and α′ -subunit protein) were selected and harvested. 2 strains (S1 and S2) had yellow seed coats and hilum. The plant height of the S1 strain was 65 centimeters. The 100-seed weight was 29.2 g. The plant height of the S2 strain was 66 centimeters and 100-seed weight was 26.2 g. The two strains selected in this research will be used to improve the new cultivar that will be free of the KTI and α′-subunit proteins.

Reductions of anti-nutritional factors of germinated soybeans by ultraviolet and infrared treatments for snack chips preparation

Ultraviolet (UV) and infrared (IR) treatments were conducted to reduce anti-nutritional factors of 5-day germinated soybean. Exposure time/duration and distance/height to UV/IR were 24/48/72 h for UV treatment at 7/17/27 cm distance and 1.0/1.5/2.0 h for IR treatment at 15/20/25 cm distance. These resulted in significant reductions (P < .05) of lipoxygenase-1, lipoxygenase-3, and trypsin inhibitor activities to 24, 83, and 50% respectively for UV treatment (17-cm distance, 24-h exposure) and 31, 95, and 98% respectively for IR treatment (15-cm distance, 1.5-h exposure). When combined, as the optimal treatment, the highest reduction was obtained (55, 97, and 99% reduction in lipoxygenase-1, lipoxygenase-3, and trypsin inhibitor activities respectively). Chemical analysis showed that chips made from UV-IR treated germinated soy had moisture, protein, starch, and lipid contents of 4.0, 46, 15, and 11 g/100 g respectively. These chips also had the lowest anti-nutritional factors due to high reductions in lipoxygenase-1 (62%), lipoxygenase-3 (98%), and trypsin inhibitor activities (100%) and low estimated glycemic index (13). However, the chips had low scores for flavor (3.3), texture (4.9), and overall impression (3.6) for their sensory analysis. Despite low in soybean anti-nutritional factors for these chips, improvement in consumer acceptance is required.

Agronomic Traits of Soybean Breeding Lines with Low Stachyose and Raffinose Contents

콩의 성숙 종실에 들어 있는 stachyose 및 raffinose 성분은 난소화성당으로 콩이나 콩 제품의 품질, 영양가치 및 가공적성을 저하시키는 것으로 알려져 있다. Stachyose 및 raffinose의 함량이 낮은 육종계통들의 농업적 형질을 평가하여 용도별 난소화성당의 함량이 낮은 콩 품종 육성을 위한 자료를 얻기 위하여 본 실험이 진행되었으며 얻어진 결과를 요약하면 다음과 같다. 1. 전체 7개의 모본을 이용하여 난소화성당의 함량이 낮은 10개의 <TEX>$F_6$</TEX> 선발 계통은 포장 평가에서 초장, 종피색, 백립중, 성숙기, 수량, 도복등 농업형질에서 다양한 차이를 보였다. 2. 883-1 선발 계통은 백립중이 14.3 g으로 수확기가 9월 21일로 조숙이며 도복이 강하여 난소화성당 저함량 조생 소립품종 육성을 위한 중간모본으로 적당하였다. 3. 백립중이 20-26 g 범위의 중립인 5개의 계통(15A1, 15D1, RS-5, RS-64, RS-70)중에서 RS-5 계통은 백립중이 20.1 g 정도이며 종자상태가 매우 우수하고 도복에 강하여 난소화성당의 함량이 낮은 중립콩 품종 육성을 위한 중간모본으로 이용성이 높았다. 4. 난소화성당의 함량이 낮아 품질 및 기능성이 우수한 장류용콩 품종 육성을 위한 중간 모본으로 14G20 선발계통은 도복이 강하며 수량성이 매우 높고 백립중이 29.7 g 정도의 대립이었다. 5. 검정종피와 녹색자엽을 가진 RS-21 계통은 도복이 강하며, 수량성이 매우 높고 백립중이 28.7 g 정도의 대립으로, 난소화성당의 함량이 낮은 특수용콩 품종 육성을 위한 중간모본으로 이용성이 높았다. Soybean [Glycine max (L.) Merr.] seed is an important dietary source of protein, oil, carbohydrates, isoflavones, and other nutrients for humans and animals. Raffinose and stachyose are the main antinutritional factors in soybean seed. They are carbohydrates belonging to the raffinose family of oligosaccharides, which are not readily digested in humans and cause flatulence or diarrhea. The genetic reduction of the raffinose and stachyose contents in mature soybean seeds will improve the nutritional value of soybean. The objective of this research was to evaluate agronomic traits with 10 <TEX>$F_6$</TEX> strains selected from breeding populations derived from a cross among seven parents. The contents of raffinose and stachyose in mature seeds were detected by high-performance liquid chromatography. Agronomic traits such as flower color, flowering date, harvesting date, lodging, plant height, seed coat color, hilum color, 100 seed weight, and yield were evaluated. Ten intermediate parents showed low raffinose and stachyose contents. The intermediate parent 883-1 had a small seed size, six intermediate parents (15A1, 15D1, RS-5, RS-33, RS-64, and RS-70) had a medium seed size, and two intermediate parents (14G20 and RS-21) had a large seed size. The intermediate parent RS-21 had a black seed coat and a green cotyledon. Four intermediate parents (883-1, 14G20, RS-5, and RS-21) had elite agronomic traits. The new intermediate parents developed through this study will be used to develop improved soybean cultivars with low contents of raffinose and stachyose.

Purification and Quantification of Kunitz Trypsin Inhibitor in Soybean Using Two-Dimensional Liquid Chromatography

Kunitz trypsin inhibitor (KTI) is one of the major antinutritional factors in soybean and results in inhibition of digestion of dietary protein. In this study, we developed a novel strategy to purify and quantify KTI from soybean using two-dimensional liquid chromatography. Lipids from ground soybean were removed using hexane after which the ground soybean was extracted with protein extraction buffer. The crude extract was first purified by weak anion exchange chromatography, and then the fraction containing KTI was further separated by size exclusion chromatography. The fraction containing KTI was collected and analyzed by SDS-PAGE and electrospray ionization mass spectrometry. Results indicated that purified KTI has a molecular mass of 20 kDa and a purity of ~98% with inhibitory activity of 2425 TIU/mg protein. This assay was used for the quantification of KTI in soybean samples. The assay showed concentrations with a range between 7.81 and 500.00 μg/mL and a limit of detection of 0.12 mg/g. The recoveries of KTI in spiked soybean samples were between 82.19% and 86.65%, and intra- and interday precisions (% CV) were less than 7.35% and 8.42%. The developed method was used to analyze soybean samples from different sources and soybean products derived from different processing techniques, which demonstrated that the developed procedure provided an accurate and sensitive tool for separation and quantification of intact KTI in soybean.

Amago salmon Oncorhynchus masou ishikawae juveniles selectively bred for growth on a low fishmeal diet exhibit a good response to the low fishmeal diet due largely to an increased feed intake with a particular preference for the diet

We have previously reported that amago salmon Oncorhynchus masou ishikawae juveniles selectively bred for growth on a low fishmeal diet exhibited superior growth performance on the low fishmeal diet compared to a control group fed the same diet. However, the physiological conditions as well as the growth and feed utilization of selected juveniles were inferior to juvenile replicates fed a fishmeal-based diet. In addition, since the selected juveniles showed improvements in feed intake for both diets relative to the counterparts of the control group, it was uncertain if the selected fish potentially had a particular preference for the low fishmeal diet. This study aimed to examine if further improvements in growth performance and physiological conditions occur in amago salmon selectively bred with a low fishmeal diet for three generations and if a selection with a fishmeal-based diet increases the acceptability of a low fishmeal diet. Juveniles (ca. 8gfish−1) of F3 amago salmon selectively bred on a low fishmeal diet (LFM-S), F3 amago salmon reared on a commercial fishmeal-based diet (FM-C) as a control, and F1 amago salmon selectively bred for growth on the fishmeal diet (FM-S), respectively, were fed either of an experimental fishmeal-based diet (FMD) or a low fishmeal diet (LFMD) for 10weeks. In LFM-S fed LFMD, 1.9 times higher weight gain (1.7 times higher in F2) was observed compared to FM-C fed LFMD. The feed efficiency ratio and feed consumption rate of LFM-S fed LFMD were also significantly higher (P<0.05) than FM-C fed LFMD. Although some improvements were observed in the hematological parameters and biliary bile acid status of LFM-S fed LFMD relative to FM-C fed LFMD, the physiological conditions as well as growth were still inferior to LFM-S fed FMD. In fish fed FMD, the growth and feed consumption of FM-S were similar to LFM-S and significantly higher than those of FM-C. By contrast, since the feed consumption of LFMD in FM-S did not increase significantly compared to FM-C, the growth of FM-S was only marginally improved relative to FM-C and inferior to LFM-S, all of which were fed LFMD. These results suggest that the superiority in growth of amago salmon selectively bred on a low fishmeal diet results from an increased feed intake with a particular preference for the diet. It is also indicated that another parental fish having physiological conditions resistant to soybean anti-nutritional factors should be introduced to the present amago salmon breeding. Statement of relevanceFish strain suitable for low fishmeal diets is demanded.

Effect of anti-nutritional factors of oilseed co-products on feed intake of pigs and poultry

Soybean, canola, camelina and flaxseed co-products from the oilseed industry are used to formulate pig and poultry feeds. However, these co-products contain various anti-nutritional factors (ANF). The major ANF in soybean and potentially co-products is trypsin inhibitor (TI). Pigs and poultry can tolerate TI levels up to 3.00 and 4.00TIU/mg in the diet, respectively. Solvent-extracted soybean meal has low TI activity (<14.0TIU/mg); most TI is destroyed during the desolventising-toasting stage of oil extraction. Thus, inclusion of soybean meal in diets for pigs and poultry does not affect feed intake and nutrient utilization. However, soybean or expeller-pressed soybean co-products can contain considerable amounts of TI (>50.0TIU/mg), implying that the raw soybean or expeller-pressed soybean co-products should be sufficiently heated to inactivate most of the TI before feeding. The major ANF in canola co-products are glucosinolates. Poultry and pigs can tolerate up to 2.00 and 2.50μmol/g of glucosinolates in their diets. Total glucosinolate content in most canola co-products is moderate (<10μmol/g). Thus, while co-products from modern canola cultivars do not affect feed intake, dietary inclusion of original canola co-products (with total glucosinolate content of ≤35μmol/g) reduced feed intake of grow-finish pigs by 80g/day and of broiler chickens in the starter phase by 4g/day. Glucosinolates and TI are the major ANF in camelina co-products. In camelina co-products, total glucosinolate content ranged from 34.4 to 36.3μmol/g and TI activity from 12 to 28TIU/mg. Camelina co-products are not solvent-extracted and thus have high TI activity. Dietary inclusion of camelina co-products reduced feed intake of broiler chickens in the starter phase by 3.4g/day. Cyanogenic glucosides are the major ANF in flaxseed co-products. Flaxseed meal contained 127mg cyanogenic glucoside/kg. Dietary inclusion of flaxseed meal reduced feed intake by poultry by 3.4g/day. In conclusion, soybean, canola, camelina and flaxseed co-products contain various ANF that reduce feed intake by pigs and poultry.

Preparation Technique of Soymilk-Based Yoghurt and it's Relation to Soybean Varieties and Anti-Nutritional Factors

The effect of soybeans varieties and the extraction ratios on the chemical composition of the resulting soymilk, additionally the effect of the preparation technique of soymilk and soy-yoghurt on the trypsin inhibitors, urease activity and phytic acid contents were investigated. Soybean seed varieties and and their structural components were analyzed for major chemical composition and soluble carbohydrates. Moreover, the changes in the soybean anti-nutritional factors affected by preparation technique of soymilk and soy-yoghurt were determined. Cotyledon of Clark variety contained significantly (p<0.05) lower moisture and total soluble sugars in particularly stachyose compared with that their values of Crawford variety. Soymilk constituents increased with decreasing the amount of water used in the extraction process (1:10 to 1:4 cotyledon: water). Soymilk processing under alkaline conditions showed completely destroyed trypsin inhibitors and urease activity and markedly reduced the amount of phytic acid in soymilk and consequently soy-yoghurt. The results showed that the effectiveness of soybean varieties and the processing technique used in the preparing of soy milk and soy-yoghurt in removing the negative effect of the anti- nutritional factors.

콩 종자에서 쿠니츠트립신인히비터와 P34 단백질의 유전

Soybean (Glycine max (L.) Merr.) protein is a high quality source for food and feed. But, antinutritional factors in the raw mature soybean are exist. Kunitz trypsin inhibitor (KTI) protein is a main antinutritional factor in soybean seed. Also, P34 protein, referred as Gly m Bd 30K, has been identified as a predominant immunodominant allergen. Genetic relationship between KTI protein and P34 protein could be useful in soybean breeding program for the genetic elimination or reduction of these factors. The objective of this study was to determine the independent inheritance or linkage between KTI protein and P34 protein in soybean seed. A total of 479 F2 seeds were obtained from the cross of 07B1 and PI567476 parents. KTI protein and relative amount of P34 protein were analysed from F2 seeds harvested from the F1 plants by using SDS-PAGE and Western blot analysis. The segregation ratios of 3 : 1 for KTI protein (353 KTI protein present : 126 KTI protein absent) and relative amount of P34 protein (363 normal amount of P34 protein : 116 low amount of P34 protein). The segregation ratio of 3 : 1 suggested that KTI protein and relative amount of P34 protein in mature soybean seed were controlled by a single major gene. The segregation ratios of 9 : 3 : 3 : 1 (266 KTI protein present, normal amount of P34 protein: 88 KTI protein present, low amount of P34 protein: 102 KTI protein absent, normal amount of P34 protein: 23 KTI protein absent, low amount of P34 protein) and Chi-square value (χ 2 =3.31, P=0.346) were observed in F2 seeds. This data showed that KTI protein was inherited independently with relative amount of P34 protein in soybean. These results will be helpful in breeding program for selecting the line with lacking KTI protein and reduced amount of P34 protein

Effects of various processed soybeans meal on growth and protein metabolism of &lt;I&gt;Cyprinus carpio&lt;/I&gt; juveniles

The effect of replacing fish meal with raw and various processed soybeans meal on growth and protein metabolism of common carp Cyprinus carpio was evaluated in an 8-week trial. The common carp fingerlings[initial body weight(5.89±0.36) g] were fed five isonitrogenous and isocaloric feeds(30% digestible protein and 15 MJ/kg digestible energy) containing SBM replacing 50% of the fish meal protein,such as raw soybean(RSB),processed soybean by chemical inactivator,processed soybean by heating,processed soybean by heat alcohol,respectively. Results showed that weight gain of control were significantly different(P0.05),but those fed RSB were significantly lower than control(P0.05),those fed processed soybeans by chemical inactivator and by heating and by heat alcohol had no significant difference,but all significantly higher than control. Protease specific activity of control in the intestine and hepatopancreas was significantly higher than those fed RSB and processed soybeans by heat alcohol,but both had no significant difference with those fed processed soybeans by chemical inactivator and by heating(P0.05). RNA of 100% fish meal and 50% processed soybean by heating in white muscle were no significant difference(P0.05),but both were significantly higher than those fed RSB and processed soybeans by heat alcohol and by chemical inactivator and by heating,RNA/DNA of 100% fish meal and 50% processed soybean by heating and by chemical inactivator in white muscle had no significant difference(P0.05),but all were higher than those fed raw soybean(RSB) and processed soybean by heat alcohol(P0.05). RNA in white muscle and serum IGF-I had a positive correlation with growth(P0.05).The degree of negative effect of soybean anti-nutritional factors on fish is anti-trypsin inhibitoragglutininsoybean antigen protein under the experimental conditions,and proper control could reduce the negative impact of soybean anti-nutritional factors on fish.

Influence of certain soybean antinutritional factors supplemented to a casein-based semipurified diet on intestinal and liver morphology in fingerling rainbow troutOncorhynchus mykiss

To investigate the cause of morphological changes occurring in the liver and intestine of rainbow trout Oncorhynchus mykiss fed defatted soybean meal (SBM)-based non-fish meal diets, morphological observations were conducted on fish fed casein-based semipurified diets supplemented with soybean antinutritional factors (soya saponin, soya isoflavone, soya lectin, oligosaccharide, Ca-phytate and their mixture). Hepatocytes and the epithelial cells in the hepatic ducts were not atrophied in any of the treatments. Lack of microvilli and pinocytotic vacuoles, and fatty degeneration of the epithelial cells were observed in the distal intestine of fish fed diets containing soya saponin. The proliferation of connective tissue in the mucosal folds and submucosa was shown in the distal intestine of fish fed the diet containing all substances including lectin. These results suggest that both saponin and lectin are the responsible factors in SBM for the occurrence of morphological changes of the distal intestine in rainbow trout fed SBM-based diets.

Comparison of nutritional and antinutritional factors in soybean and fababean seeds with or without cortex

The composition and contents of nutritional factors such as proteins, lipids, carbohydrates, fibers, amino acids, and antinutritional factors such as trypsin inhibitors, phytic acid, and tannins were compared in soybean and fababean seeds with emphasis placed on the nutritional improvement of the seeds by cortex removal. Protein hydrolysis analysis for both whole seeds and seed with cortex removed revealed the presence of a large amount of lysine, arginine, aspartic acid, glutamic acid, glycine, and leucine while these seeds contained a low level of tryptophan, cystine, and methionine. Some antinutritional factors such as trypsin inhibitors, phytic acid, and tannins were detected in soybean and fababean seeds: phytic acid content and trypsin inhibitor activity were higher in soybean seeds than in fababean seeds while the difference in the tannin content was less pronounced. It was found that most of the tannins occurred in the cortex of the soybean and fababean seeds. Tannins are polyphenolic compounds that readily form indigestible complexes with proteins and other macromolecules under specific environmental conditions. By removal of the cortex, tannins were almost completely eliminated without changes in the protein composition and amino acids. From these results, it is assumed that since soybean and fababean seeds contained a high concentration of antinutritional factors in the cortex such as tannins, the utilization of the legume seeds after removal of all of the cortex is suitable for human diet or industrial products.